Hi: I have recently purchased the following car, a Jaguar S type 2003 2.5litre SE Auto

My problem is that the heating is on all the time.

There are some possible clues:

1. The Air Conditioning not working but there is a full supply of gas in the system
2. The ambient temperature on the display is lower than it actually is. Lower by about 5C
3. I have had “Engine Coolant Low” on the display but this has been dealt with by the dealer who fitted a new ?? header tank

Any help would be appreciated

 

See the FAQs

 

Apologies. I'm new to this.

 

No worries, we were all "new at this" at some point... As JagV8 stated, look in the FAQ under DCCV (Dual Climate Control Valve), sometimes referred to as the Heater Valve. Most likely that is your issue. Those things seem to fail like clock work!

 

As Jeff says, we all were once so don't worry I was just in a hurry and trying to get you pointed to the right place.

 

I will give you my recent experience it may be of help - Passenger side always hot - driver side adjustable. changed DCCV as coil reading bad, no luck, had wiring loom checked - no luck, so now its pointing at the RCCM (remote climate control module) as my car has navigation so the module is mounted above the glove box. Removed glovebox and took out module - opened module and as expected found blown track on printed circuit board, caused by over current due to shorted coil on DCCV. repaired track and all working okay. this saved me £450-500 uk money !!! as this is what Jaguar charge for replacement module
There are other causes ie - temp sensors and pressure sensors etc that can have an effect on the performance of the climate control, but the above is a good basic way to start the diagnosis - I hope this helps.